Scientists believed Covid leaked from Wuhan lab, but feared debate could hurt

> We used high-quality surgical masks that had had a filtration efficiency of 95% [standard deviation (SD) = 1%]; this is substantially higher than the filtration efficiency of the cloth masks we designed, which had a filtration efficiency of 37% (SD = 6%). These cloth masks had substantially higher filtration than common commercial 3-ply cotton masks, but lower than hybrid masks that use materials not commonly available for community members in low-resource settings (54).

The key result:

> We find clear evidence that surgical masks lead to a relative reduction in symptomatic seroprevalence of 11.1% (aPR = 0.89 [0.78,1.00]; control prevalence = 0.81%; treatment prevalence = 0.72%). Although the point estimates for cloth masks suggests that they reduce risk, the confidence limits include both an effect size similar to surgical masks and no effect at all. (aPR = 0.94 [0.78,1.10]; control: 0.67%; treatment: 0.61%).

It's a shame that even with such a large study, the phenomenon is so noisy that we can't get a strong signal here. But i think the takeaway is that masking has an effect, but it is rather small.

There's a lot more detail in the paper. Including this gem:

> We find no evidence that any of our village-level or household-level treatments, other than mask color, impacted mask-wearing. For mask-color, we see marginally significant differences, small in magnitude. In surgical mask villages, blue masks were more likely to be observed than green (adjusted percentage point difference = 0.03, [-0.00,0.06]), and in cloth mask villages, red more likely than purple (adjusted percentage point difference = -0.02, [-0.04,-0.00]). Text message reminders, incentives for village-leaders, or explicit commitment signals explain little of the observed increase in mask-wearing. Compared to self-protection messaging alone, altruistic messaging had no greater impact on mask-wearing, and twice-weekly text messages and a verbal commitment had no significant effects.

So that makes it ok for them to lie? I do not agree. And the trust is lost as a result.

They should have explained that we should prioritize masks for health care professionals if that was their reasoning.

Speculation about motives is difficult, my most prominent idea is that a subset of scientists agreed it was better to craft a noble lie than to be transparent with their ideas. Repeating a lie often enough so that people believe it to be true is a law of propaganda.

> lies, distortions of the truth, misunderstandings, assumptions, ignorance

I don't see how a "distortion of the truth" has less requirements for a motive than propaganda. What do you believe was the motivation to distort the truth? If you have an idea I would gladly entertain it. I don't think "misunderstanding" fits the case where people were targeted for dissenting views.

> a contagion leak makes complete sense with no conspiracy theories needed

Yes indeed, this would not have needed any conspiracies at all, but we got one for political reasons as the "official" message was crafted to deny the possibility of a leak outright by a subset of the scientific community. For personal gratification or just to calm the public or any other reason is of secondary importance here. The fact remains that there were attempts to suppress such views.

> the resulting pandemic could be used as an instrument to cause and inflict political harm in order benefit rivals or perhaps entire states and regimes.

The problem is the lack of transparency and intentional lies, this is off topic.

If it was an accident, there must be consequences for research like this. Maybe it has to be disallowed, perhaps more security is needed. I can see how such measures might run counter to the interest of the group that came up with the idea to neglect that possibility. Just to make it very clear, that is speculation about a motive and is not substantiated. Substantiated was the lack of truthful information.